Adjusting the Screen Controls
The screen contrast and brightness controls are located at the bottom of the screen.
Slide the contrast control to the right to increase the contrast, or to the left to decrease it. On dual scan screens only, slide the brightness control to the right to lighten the screen, or to the left to darken it. On active matrix screens, it isn’t necessary to adjust the contrast.
Unless you need a bright screen, you can extend battery life and save energy by making it dimmer.